Thanks for the quick responses. You all seem to be right, a few of them moved quickly up the glass but they have all stopped at the top of the water and most of them have already headed back down. I just got these inverts from SWF today and they are all doing great and started doing there jobs as soon as i introduced them into the tank: Cleaner shrimp, peppermint shrimp, hermit crabs, astrea snails, cerith snails & nassarius snails.